#337DD0
Closest named color: Windows Blue (#3778BF). oklch(58.5% 0.147 253.7), rgb(51, 125, 208).
Aa
Black text reads best on this color (4.98:1).
About this color
#337DD0 is a medium-dark, vivid blue. In OKLCH its lightness is 59%, its chroma 0.147 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.027 away. Black text reads best on it, at 4.98:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | vivid (0.147) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.98:1 |
| White text | 4.21:1 |
Values
| HEX | #337DD0 |
| RGB | rgb(51, 125, 208) |
| HSL | hsl(212, 63%, 51%) |
| OKLCH | oklch(58.5% 0.147 253.7) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #337DD0 | 4.21:1 | AA large text | Lc -74.2 | Content text, not long reading |
| Black text on #337DD0 | 4.98:1 | AA | Lc 35.4 | Non-text elements, placeholder text |
| #337DD0 text on white | 4.21:1 | AA large text | Lc 68.7 | Content text, not long reading |
| #337DD0 text on black | 4.98:1 | AA | Lc -33.0 | Non-text elements, placeholder text |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 600.
-
Step 50
50
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF7
oklch(93.6% 0.019 252.9)
-
Step 200
200
#C9DBF2
oklch(88.5% 0.037 254.6)
-
Step 300
300
#A3C4EB
oklch(81% 0.066 252.8)
-
Step 400
400
#71A4E1
oklch(70.7% 0.105 253.6)
-
Step 500
500
#498CD9
oklch(63.2% 0.135 253.5)
-
Step 600
600 (this color)
#337DD0
oklch(58.5% 0.147 253.7)
-
Step 700
700
#1B61AB
oklch(49.1% 0.136 253.6)
-
Step 800
800
#194F8B
oklch(42.6% 0.114 254)
-
Step 900
900
#1C426F
oklch(37.6% 0.089 254.4)
-
Step 950
950
#112741
oklch(26.9% 0.056 253.9)
#337DD0 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #5583D3 | 0.037 |
| Deuteranopia (no green cones) | #3C75CE | 0.021 |
| Tritanopia (no blue cones) | #00919C | 0.113 |
| Achromatopsia (no color) | #7B7B7B | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337DD0
#337DD0
oklch(58.5% 0.147 253.7)
- #A76E00
#A76E00
oklch(58.4% 0.124 73.4)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #337DD0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.027
- Water Blue #0E87CC ΔE 0.031
- Cool Blue #4984B8 ΔE 0.049
- Steel Blue #4682B4 ΔE 0.050
- Nice Blue #107AB0 ΔE 0.055
- Dark Sky Blue #448EE4 ΔE 0.055
- Royal Blue #4169E1 ΔE 0.061
- Flat Blue #3C73A8 ΔE 0.063
Use #337DD0 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.